The present invention is related to a carrier for pipette tips, for those in automatic machines in particular. Furthermore, the invention relates to a distance piece for holding an upper plate with a plurality of holes for inserting pipette tips spaced from a lower plate with a plurality of holes for holding pipette tips.
Carriers for pipette tips serve for keeping and providing pipette tips made of plastic material for utilisation. They have an edge with four upwardly projecting side walls and a plate, disposed on the upper edge of the frame and having a plurality of holes in a matrix arrangement. Pipette tips are put into the holes from out the upside, wherein they do not fall through the holes due to a diameter that widens towards the upside, or due to a collar. The frame is adapted to be put onto a support with its lower edge or a bottom. The pipette tips are held at a distance from the support by the carrier. One or plural pipette tips may be taken out of the carrier by means of a pipetting- or metering apparatus, respectively. For this purpose, the metering apparatus is pressed into the upper opening of one or plural pipette tips with one or plural studs. After use, the pipette tips are normally put into a carrier or given off into a container with the aid of a throw-off device of the metering apparatus, in order to be disposed of.
Carriers for pipette tips are known wherein the frame is covered by a bottom at the downside, and by a detachable cover cap on the upside. In these box-like carriers, the pipette tips are protected against contaminations. Before taking out pipette tips, the cover cap has to be removed.
From WO 00/51899 A1, a refill package for re-usable carriers for pipette tips is known. The refill package comprises a plate with holes in a matrix arrangement, into which pipette tips are inserted, and a flexible cover cap in which the plate is held. When putting the cover cap onto the upper edge of a carrier, the side walls of the cover cap are laterally deflected, so that the plate clamped in there between is released. As a consequence, the plate with the pipette tips falls into a reception piece of the carrier that is surrounded by an enclosure. Refilling the carrier with pipette tips and taking out the plate with pipette tips from the carrier are performed manually.
In automatic metering machines and automatic laboratory machines (“workstations”) that include metering apparatuses, pipette tips made of plastic material are frequently employed. Automatic metering machines and automatic laboratory machines will be designated as “automatic machines” in the following. The known refill package is not well suited for the utilisation in automatic machines. Displacement of the cover cap by an automatic machine in order to separate plate and cover cap would be problematic due to the cover cap's flexibility. When the plate is disposed in the carrier, the lateral enclosure encumbers the removal by an automatic machine.
From U.S. Pat. No. 6,221,317 B1, a box for pipette tips is known which features a lower part with a bottom and side walls, which end up in support surfaces at the upside. A plurality of locking elements is asymmetrically disposed on the support surfaces. A plurality of inner walls projecting upward from the bottom is adjacent to a plurality of inner accommodations. A plate portion features a first set of holes, into which the locking elements are inserted. Further, it has a second set of holes for the insertion of pipette tips. The locking elements are realised as locking pins, which engage by frictional fit into the first set of holes of the plate. Thus, plate and lower part are detachably fixed to each other by way of the pins and bores. However, detaching the plate from the lower part is only possible by the expenditure of a force that is greater than the weight force of lower part and plate. The user can choose among plates having 96, 348 an 1536 holes for inserting pipette tips. He can fix the selected plate on the lower part by way of the locking pins and the holes. Thereafter, he may insert the pipette tips into the holes and place a cover cap over the plate.
The grid-like subdivision of the interior space provides the box with a stiffness sufficient for handling by an automatic machine. Automatic refilling of pipette tips into the box would be a problem. In particular, replacing a plate by a plate equipped with new syringes would be hard to perform for an automatic machine. That is to say, this would require a very accurate positioning of the holes above the locking pins that must be pressed in, and an accurate insertion of the pipette tip into the interior space that is subdivided by inner walls. This could not be managed by conventional automatic machines. Thus, it is a disadvantage of such a box that the pipette tips hit the grid-like subdivision when being inserted, and fall out of the plate. From this document, it is also known to stack several pipette tip boxes on top of each other in order to combine a larger number of pipette tips. This arrangement requires much space and material.
The sales unit with refill packages for nestable pipette tips Tip One® from the company USA Scientific comprises pipette tips, which are arranged in plates stacked on top of each other, wherein the pipette tips are inserted into each other. The lowermost plate is inserted into a box and the uppermost plate is covered with a cover. In order to remove pipette tips by means of a pipette, a plate is removed from the stack and inserted into a box. This system saves space and material. However, it is only suitable for nestable pipette tips. Nestable pipette tips are pipette tips that are nestable due to complementary inner and outer shapes, in particular inner and outer conical shapes with the same opening angle. The system is not suitable for non-nestable pipette tips, in particular for pipette tips with a cylindrical section and for filter pipette tips, because they are only partially nestable and hereby wedge together easily or hit the filter. As a result, during removal of an upper plate, pipette tips from a lower plate would be taken along or respectively the function of the filter pipette tips would be impaired.
From U.S. Pat. No. 5,366,088, a carrier for pipette tips is known, which has five racks stacked one above the other. Each rack comprises a plate with a plurality of holes for removing pipette tips. From the edges of each plate, side walls project further downwards than the pipette tips inserted therein. In a stacked arrangement, the lowermost rack is inserted into a box, wherein the side walls engage in a recess in the box and support themselves on the bottom of the box via a base plate. Five racks are stacked one above the other, wherein the lower edges of the side walls of an upper rack support themselves on the upper edge of the side walls of a lower rack. Inserted pipette tips thereby engage with each other in racks stacked one above the other. A hood-like cover element covers the uppermost rack. A plurality of pipette tips is hereby combined in a space-saving manner. For removing pipette tips by means of a pipette, individual racks can be removed from the stack and made available in the box. This carrier is suitable for nestable pipette tips. The stacking of several racks one above the other is difficult, because small displacements of pipette tips can lead to them not engaging correctly with each other. The apron permanently connected with the plate provides a rigid stack pattern and covers the view of the contents. Moreover, the apron largely prevents a sufficient sterilization.
Non-nestable pipette tips are combined in boxes stacked one above the other as described in U.S. Pat. No. 6,221,317 B1.
In the case of the sales unit with refill packages for non-nestable pipette tips Tip One® from the company USA Scientific, two plates with 96 pipette tips each are each inserted into deep-drawn double shells. Each double shell is closed by a cover. Five double shells are stacked one above the other to form one unit with a total of 960 pipette tips. This arrangement also takes up a lot of space and requires a lot of material.
Starting from this, the present invention is based on the objective to provide a carrier for pipette tips which is particularly suited for the utilisation in automatic machines. That is to say, the carrier is distinguished by its particular stability and its suitability for being handled by automatic elements (like gripping arms, metering head e.g.). Thus, an essential aspect of the objective is to provide a carrier whose plate and frame cannot be separated without intent, by errors of the automatic machine e.g., but whose elements (plate and frame) can be detached simply when this is intended.
This objective is achieved by a carrier with the features of embodiment 1. Advantageous embodiments of the carrier are indicated in the subclaims.
Furthermore, the object of the invention is to create a device for the space- and material-saving stacking of non-nestable pipette tips, only partially insertable into each other, in several plates one above the other.                The carrier for pipette tips of the present invention has:        a frame, featuring four side walls,        a plate with a plurality of holes for inserting pipette tips, and        means for detachably connecting the frame and the plate,        that have contact surfaces on the upper edge of the frame and on the underside of the plate, which touch each other when the plate is put onto the frame, and        that have guiding elements directed transversally to the contact surfaces on the frame and on the plate, which engage into each other with lateral clearance when the plate is put onto the frame.        
In the carrier of the present invention, the means for detachably connecting the frame and the plate have contact surfaces touching each other on the upper edge of the frame and on the lower side of the plate. Further, they comprise guiding elements of carrier and plate that engage into each other transversally to the contact surfaces with lateral clearance. The guiding elements are preferably aligned vertically to the contact surfaces. Yet, they may also be aligned inclinedly to the contact surfaces. Due to the arrangement of the contact surfaces, the plate is covered laterally not at all or only in parts by the frame. As a consequence, a gripping tool of an automatic machine can have access to the edges of the plate, in order to put a plate onto the frame or to take it away from the frame. Thus, the edges of the plate are adapted for the transportation by a gripping tool. The plate is relatively stiff in the direction of this load by a gripping tool, so that it resists the clamping force of the gripping tool and can be safely held by the same. By the engaging guiding elements of the means for detachably connecting, the plate is safely held on the frame. The guiding elements of frame and plate engage into each other with lateral clearance. The joining of plate and frame is facilitated by this clearance between the engaging guiding elements, so that it may be performed more easily automatically. This holds also for lifting the plate from the frame when an empty plate is to be replaced by a filled plate. The parts of plate and frame engaging with clearance match can compensate for inaccuracies of an automatically operated gripping device. A plate pre-filled with pipette tips can be put onto the frame, so that the carrier can be filled with pipette tips automatically. The plate may feature e.g. 24, 48, 96, 384 or 1536 holes for inserting pipette tips. In case that a hooked-up pipette tip occurs in an erroneous withdrawal by a metering tool, and the plate is lifted along with the pipette tip through this and is in danger to fall out, there will be a toe-in between the guiding elements that engage with lateral clearance resulting in a release of the hooked-up pipette tip from the plate, so that the plate slips back into the frame into its original position. Thus, this intended toe-in prevents unintended separation of the plate from the frame and increases the safety of the automatic processes. In particular, the continuation of the automatic pipetting process is made sure in this way, without that any manual intervention is necessary.
The present invention incorporates embodiments wherein the frame and the plate are each one provided with only two guiding elements, which can be brought into engagement with each other. Preferably, the frame and the plate have plural guiding elements each, four in particular, a guiding element of the plate being associated to each guiding element of the frame and the associated guiding elements being adapted to be brought into engagement with each other. The associated guiding elements of frame and plate are arranged on different positions of frame and plate. They are preferably arranged at opposing side walls of the frame and at opposing edges of the plate. Further preferably, they are arranged at diametrically opposing positions of the side walls and of the edges of the plate.
The guiding elements that are adapted to be brought into engagement with lateral clearance can be realised in different ways. For instance, it is dealt with an upper opening of the frame and a collar at the lower side of the plate that is adapted to be inserted into the upper opening with clearance. According to a preferred embodiment, the guiding elements feature columns and bores suitable for insertion of the columns with lateral clearance, and/or ribs and grooves that are suitable for insertion of the ribs with lateral clearance. Due to the clearance match, the inner diameter of the bores or the width of the grooves, respectively, exceeds the outer diameter of the columns or the wall width of the ribs, respectively. According to a further embodiment, the columns and/or the ribs project from the upper edge of the frame and the plate features the bores and/or grooves at the underside. However, the invention incorporates also embodiments in which the columns and/or the ribs project from the underside of the plate and the upper edge of the frame features the bores and/or grooves. Finally, embodiments are incorporated in which the upper edge of the frame features columns and/or ribs and bores and/or grooves, and the underside of the plate features corresponding bores and/or grooves and columns and/or ribs. The bores may be through bores or blind bores, and the grooves may have a groove bottom or may be realised as through slits.
The columns may have different shapes. For instance, they may be cylindrical and have a circular or polygonal cross section. The same holds for the bores in a corresponding way. The ribs may have a constant wall thickness. Further, they may have a straight, angled or curved course. Corresponding holds for the grooves.
According to a preferred embodiment, the columns taper at least in sections in the direction towards their free end, and/or the bores widen up at least in sections in the direction towards their insertion openings for the columns. The columns may also taper over their entire height and/or the bores may widen up over their entire depth. Further, the ribs can taper at least in sections in the direction towards their free end, and the grooves may widen up at least in sections in the direction towards their insertion openings for the ribs. But however, the ribs may taper over their entire height and/or the grooves may widen up over their entire depth. The tapering columns or ribs and the widening bores or grooves facilitate the joining of the plate with the frame, and thus they favour the handling by automatic machines. According to a further embodiment, the columns and the bores are arranged on the corners of the frame and the plate. Further, the invention incorporates embodiments wherein the columns and the bores are arranged between the corners of the frame and the plate.
According to a further embodiment, the frame features a waistline. The waistline favours a positive fit and safe grasping of the entire carrier by way of a gripping device of an automatic machine. Thus, the waistline is favourable for a safe and accurate positioning of the entire carrier. Due to the waistline, the carrier may be grasped safely with less gripping force. In principle it is sufficient that the waistline be formed by two opposing side walls of the frame. Preferably it is formed between all the opposing side walls, so that the carrier can be grasped safely from out two directions.
For instance, the waistline may be formed by deepenings in the outer side of opposing side walls. According to one embodiment, the waistline is limited at its upside by an outwardly protruding upper projection of the frame. This limitation can prevent the carrier from falling out of a gripping device. Further, the waistline can be limited at the downside by an outwardly protruding lower projection of the frame. By the shaping of the waistline, the bending force when it is grasped by way of a gripping device can be optimised, so that the frame resists the loads through the gripping device.
The present invention incorporates embodiments wherein the frame is open at the downside. This frame is adapted to be put onto a support with a lower edge. According to one embodiment, the frame is closed at the downside by a bottom. The bottom protects pipette tips against contaminations from out the downside. The lower projection may be formed by an edge of the bottom that projects towards the outside over the side walls.
According to a further embodiment, the dimensions of the ground area of the frame coincide with the dimensions of the ground area of microtiter plates according to the standard of the Society for Biomolecular Screening (SBS). This standard has been published by the American National Standards Institute (ANSI) with the designation ANSI/SBS 1-2004 and is designated as the “SBS Standard” in the following. According to this, a microtiter plate has a ground area (“Footprint”) with a length of 127.76 mm and a width of 85.48 mm. The ground area of the frame has the same dimensions. Conventional automatic machines feature bearing positions for microtiter plates that have the mentioned dimensions. These bearing positions are provided with guiding- and clamping devices which are matched to the mentioned dimensions. These bearing positions and guiding- and clamping devices can be used for positioning the carrier that has a ground area according to SBS Standard. A waistline permits to conform with the standard even in case that the frame has a lateral projection at the upside for supporting it on a gripping tool.
According to a preferred embodiment, the frame has a free cross section between the side walls. In this embodiment, the side walls are not connected between each other by inner walls, like in the carrier according to U.S. Pat. No. 6,221,317 B1. As a consequence, putting up a plate with inserted pipette tips cannot be disturbed in that the pipette tips collide with inner walls in the frame. According to a further embodiment, the side walls are provide with vertically running ribs on their inner side, which stiffen the side walls. The vertically running ribs can be dimensioned such that they grasp only slightly into the inner space of the frame and a great free cross section for accommodating pipette tips remains between the side walls.
According to one embodiment, the plate features a gripping edge projecting beyond the upper side of the plate on each one of at least two opposite edges. The gripping edges can be used as additional contact surfaces by the gripping tool of an automatic machine. Further, the gripping edges can serve as protection- and gripping edges for preventing the contamination of the pipette tips in the manual assembly of a carrier with the plate. Preferably, the gripping edges project from the upper side of the plate at least as high as the pipette tips that are inserted into the plate. The gripping edges may be arranged on the two longitudinal edges of the plate. In addition or instead of this, they may also be arranged on the two front side edges of the plate.
According to a further embodiment, the carrier has a cover cap with a cover cap bottom and cover cap side walls projecting towards the downside from the edge of the cover cap bottom which can be put onto the frame. The cover cap covers pipette tips at the topside that are held in the frame by way of a plate. In order to position the cover cap on the carrier, the frame has a circumferential shoulder on the outside onto which the cover cap can be put with the lower edge of the cover cap side walls. The accurate positioning favours the sealing of the cover cap with respect to the frame. The circumferential shoulder on the outside can be formed on an outwardly projecting upper projection which limits a waistline.
According to a further embodiment, the cover cap has an edge surface limiting the shoulder at the outside, which is aligned with a further edge surface that limits at least the lower edge of the cover cap side walls at the outside when the cover cap is put up. The edge surfaces aligned with each other can be used for attaching a sealing adhesive tape. Sterile custody of pipette tips in the carrier can be made sure by the adhesive tape.
According to a further embodiment, the dimensions of the ground area of the frame exceed the outer dimensions of the frame in the region of the upper edge surface. By this, it can be made sure that the dimensions of the carrier do not exceed the SBS-format even when an adhesive tape for sealing a cover cap is attached. The difference of the dimensions is preferably 0.05 to 1 mm. More preferably it is 0.1 to 0.5 mm.
According to a further embodiment, the bottom is a hollow bottom having a downwardly projecting enclosure, the bottom being adapted to be put onto the upper edge of the cover cap. The enclosure can laterally grasp over the cover cap side walls or guiding bridges that project upward from the cover cap. This permits safe stacking of several carriers one above the other.
According to a further embodiment, the cover cap features deepenings in the outer sides of two opposing cover cap side walls. The deepenings permit a positively fitting contact to a gripping tool of an automatic machine, and so they favour the automatic lifting of the cover cap. Further, when the cover cap is made transparent, the deepenings favour the read-out of a tag on the upper edge of the carrier, which can be realised as a bar code for instance.
Furthermore, the object is achieved by a device with the features of embodiment 22. Advantageous embodiments of the device are specified in the embodiments described herein.
The distance piece according to the invention for holding an upper plate with a plurality of holes for inserting pipette tips spaced from a lower plate with a plurality of holes for holding pipette tips is frame-shaped, has an intermediate bottom with a plurality of additional holes for the lateral guiding of pipette tips, can be placed onto the bottom side of the upper plate with its top side outside of the holes and can be placed with its bottom side onto the top side of the lower plate or of pipette tips held in the lower plate.
The distance piece bridges the distance between an upper and a lower plate, which is required in order to partially insert into each other pipette tips that are inserted into the upper and the lower plate, non-nestable and partially insertable into each other. The distance piece can hereby ensure that the pipette tips are only loosely inserted into each other and do not clamp together or respectively support themselves on the filters so that the upper plate can be easily removed from the distance piece without taking along pipette tips from the lower plate or respectively damaging filters.
The distance piece can be used to hold plates, which can also be used to hold conical pipette tips. As a result, uniform plates can be used for nestable and for non-nestable pipette tips. Moreover, the frame-shaped distance piece protects the pipette tips from contamination. The intermediate bottom with the additional holes for laterally guiding pipette tips holds the pipette tips in vertical alignment. Thus, the arrangement of the plate and distance piece with inserted pipette tips is easily stackable and transferrable into a box for receiving pipette tips. Since the installation height of the distance piece is dimensioned such that the pipette tips can be partially inserted into each other without clamping in each other or respectively loading a filter, material is saved in comparison with boxes stacked on top of each other and with racks stacked on top of each other with deeply down-turned side walls. When removing pipette tips, the distance piece does not have to support the plate so that its distance piece side walls can be designed in a particularly thin and material-saving manner.
The plates stacked on top of each other with the help of the distance pieces are housable in a correspondingly small outer packaging. Further material is hereby saved. The non-nestable pipette tips are housed in one stack in the smallest space.
According to one embodiment, the distance piece has distance piece side walls opening towards the top so that several same distance pieces are stackable within each other. The stackability is advantageous for the space-saving storage before use of the distance piece and for reducing the volume of waste after discharging the pipette tips from the upper plate.
According to a further embodiment, the distance piece has locking elements on the upper edge, which are lockable with locking elements on the bottom side of the upper plate. Through the locking, the upper plate is combined with the distance piece to form one unit, which can be easily removed from the stack and can be transferred into a box for the discharging of the pipette tips. The distance piece hereby aligns the pipette tips and protects them from contamination. The locking of the distance piece with the upper plate is preferably releasable so that after discharging the pipette tips the distance piece can be released from the plate. It can subsequently be stacked with further distance pieces in a space-saving manner. Furthermore, this is advantageous for separate disposal of the distance pieces and plate if they are made of different materials.
According to a further embodiment, the distance piece has locking tabs protruding outwards on the upper edge from at least two opposite distance piece side walls with insertion chamfers for locking behind locking edges on an apron-like downwardly protruding edge area of the upper plate. A simple and secure locking of distance piece and plate is hereby promoted and can also be established by an automatic machine during production.
According to a further embodiment, stiffening ribs are present between the locking tabs and distance piece side walls. The stiffening ribs protect the locking tabs from damage.
According to a further embodiment, the intermediate bottom has ribs on the top side between the holes, which extend from a distance piece side wall to the opposite distance piece side wall. The ribs reinforce the distance piece so that it can be produced with a reduced amount of material. Moreover, they facilitate the insertion of pipette tips during production.
According to a further embodiment, the intermediate bottom bears intersecting ribs. Even stronger rigidity and improved material savings are hereby achieved.
According to a further embodiment, the distance piece has guiding elements protruding downwards and/or upwards from the intermediate bottom for lateral guiding on pipette tips, which are held by a lower and/or by an upper plate. The guiding elements stabilize a stack of several plates and at least one distance piece in that they laterally guide the distance piece on the pipette tips.
According to a further embodiment, the guiding elements comprise lower and/or upper sections of distance piece side walls, which protrude downwards and/or upwards from the intermediate bottom in order to support themselves on the top side and/or the bottom side of a lower and/or upper plate and to be guided on the periphery of pipette tips, which are inserted near the edge into the lower and/or upper plate. The invention includes embodiments, in which sections of distance piece side walls protrude from the intermediate bottom exclusively upwards or exclusively downwards. Furthermore, it includes embodiments, in which sections of distance piece side walls protrude from the intermediate bottom both upwards as well as downwards. The protruding sections of distance piece side walls are laterally supported on the pipette tips, which are inserted near the edge into the plate, on which these sections of the distance piece side walls are supported.
According to a further embodiment, the intermediate bottom bears protruding guiding elements on the bottom side between the additional holes. The intermediate bottom is supported with the edge of its additional holes on the heads of the pipette tips, which are inserted into the lower plate. The diameter of the additional holes should be dimensioned such that the pipette tips held in the upper plate can freely immerse and the round areas of the additional holes can be supported on the heads of the pipette tips held in the lower plate. The guiding elements protruding between the additional holes support the distance piece laterally on the heads of the pipette tips, which are arranged near the edge or at a further distance from the edge. These guiding elements are designed according to one embodiment as strip-like projections. Other geometries of these guiding elements are possible. For example, each guiding element can extend annularly around a hole in order to laterally support itself on the upper periphery of a pipette tip head. Guiding elements protruding between the holes make it possible to do without guiding elements protruding downward in an apron-like manner. In this embodiment, the intermediate bottom is connected with the lower edge of the side walls. Further material can hereby be saved. Furthermore, this design promotes the view of the pipette tips from the side in the stack and sterilization of the tips.
The distance piece is preferably made of plastic. It is preferably injection-molded. It is preferably made of one piece. It is preferably made of polypropylene (PP).                Furthermore, the invention comprises a carrier for pipette tips with        a frame or box having four side walls,        several plates with a plurality of holes for inserting pipette tips,        pipette tips inserted into the holes of the plates,        means for releasably connecting the frame or the box with a plate,        a lower plate, which is connected via the means for releasably connecting with the frame or the box,        a distance piece placed with the bottom side on the lower plate or on the pipette tips in the plate according to one of embodiments 22 to 33 and        an upper plate, which is supported with the bottom side on the top side of the distance piece.        
The frame or box and the plate can be designed like the carrier for pipette tips according to one of embodiments 1 to 20 described herein. Furthermore, the frame or box and plate can also be designed without the guiding elements of the carrier of embodiments 1 to 20 described herein. The carrier enables a space- and material-saving housing of at least two plates equipped with pipette tips. After transfer of the upper plate into a box, the pipette tips inserted into it can be discharged by means of a pipette.
According to a preferred embodiment, several arrangements of distance piece and plate are stacked on top of each other.
According to a further embodiment, the upper plates have, on an apron-like, downwardly protruding edge area, inwardly protruding locking tabs and the locking elements of the distance piece are locked with the locking tabs of the upper plate. The locking is easily established by bending the apron-like, downwardly protruding edge of the upper plates outward and is releasable by expanding this edge. The apron-like, downwardly protruding edge also stabilizes the plate.
According to a further embodiment, a hood-like cover covering the pipette tips on the top and on the side is placed on the top on the uppermost plate. The pipette tips in the uppermost plate are hereby also protected from contamination.
According to a further embodiment, the plates have an outwardly protruding, circumferential step and the cover is placed on the top side of the step of the uppermost plate. The cover is hereby advantageously guided on the uppermost plate.
According to a further embodiment, the diameter of the additional holes of the intermediate bottom is the same size or smaller than the diameter of the holes of the plate and smaller than the outer diameter of the heads of the pipette tips.
According to a further embodiment, the carrier comprises several same plates and/or several same distance pieces. The carrier can thus be assembled from uniform components.
The plates are preferably made of plastic. They are preferably injection-molded. They are preferably made of one piece. They are preferably made of polypropylene (PP).
According to a further embodiment, the carrier is surrounded by a strap and/or shrink-wrapped with a film. A stable sales unit protected from contamination is hereby provided. The outer packaging is alternatively a folding box. The band and/or the film and/or the folding box are preferably made of plastic, preferably of polypropylene or another plastic, which permits autoclaving.
Finally, the invention relates to an arrangement made up of several carriers according to one of the embodiments 34 to 39, each of which are surrounded with an edge and shrink-wrapped altogether with a film. A stable sales unit protected from contamination with a particularly large number of pipette tips is hereby provided.
According to a further embodiment, the carrier comprises a frame-shaped distance piece, which is adapted to be put onto the upper side of a plate with its lower edge outside of the holes, and with its upper edge onto the lower side of a plate outside of the holes. The distance piece permits to stack several plates filled with pipette tips onto one single frame. In this, the lowermost plate filled with pipette tips is arranged directly on the frame. A distance piece is arranged on this lowermost plate, and on the distance piece in turn a plate filled with pipette tips. If need be, further distance pieces and plates are alternately disposed on this. The distance piece prevents that pipette tips arranged in different plates are pressed into each other, and that the pipette tips of a plate disposed below are lifted along when a plate is lifted.
According to one embodiment, the distance piece has an intermediate bottom with further holes. When a plate with inserted pipette tips is put onto the distance piece, the pipette tips are guided by the further holes, so that they are safely guided into the upper openings of pipette tips that are inserted into a plate that is disposed below. Preferably, these further holes are dimensioned such that they prevent pipette tips of a plate disposed below from being lifted along when a plate with inserted pipette tips is lifted. The pipette tips of the deeper disposed plate are held on the holes and fall back into the deeper disposed plate. The stack is positioned by the partly intermeshed pipette tips in plates that are disposed one above the other. A cover cap may be slackly positioned on the uppermost plate.